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ITT Xtra XP 80286 6MHz Clone & An ITT Memory Expansion Board

So I have a fairly hard to find ITT Xtra XP 80286 6MHz system that is basically in mint condition. It just has two 360K floppy drives and no hard drive. It also has 640K on-board. I found this very hard to find ITT 8-bit ISA memory expansion board and from the photos you can see it was specifically made for this motherboard. Without this board installed and playing with the memory dip switches on the motherboard I can toggle it between 512K and 640K. Bank 1 is 128K and Bank 2 is 512K. On the expansion board there is 512K on bank 3 and an empty bank 4. When I turn the machine on without the memory board it reads correctly 640K during post and tests all good with the CheckIt utility software. When I add the expansion board, at post it now will read 1536K RAM which makes no sense unless bank 4 was populated, but it's not. Worse yet DOS does not see the board with Himem.sys. From what I am reading this board would be handled as expanded memory??? Either way, post sees it, but DOS does not. Does this mean I need a driver for this board? If I do I think I am screwed because I can't find a driver for this memory expansion board anywhere on the Interwebs and it did not come with one when I bought it. If you have any insight on this I would much appreciate it. Thanks.

640 to 1024KB is reserved, so perhaps in the memory count it's jumping those 384KB to show where the memory ends. [Edit: I had another theory, but after seeing 4164's, realized I was wrong]

I'd also take a guess that it uses expanded memory (EMS). Not too surprising as EMS can actually be more useful for DOS software a lot of the time. Sometimes generic or common brand EMS drivers will work for clone stuff because it was a bit of a standard. A lot of my no-name brand EMS boards run just fine off Intel EMS drivers - guessing the IO port can be fun though and there is no guarantees.

I have the 8088 version of that machine, but finding much about it or parts combined with it having sat under someone's house for a long period of time, equated to me not getting it running. No idea if this post helps, but cool to see another ITT!

I believe it does not use EMS. It was released about the same time as the EMS was first announced. It may support the earlier Tall Tree standard or its own memory design. The disk cache and print spooler included with ITT's own DOS seem to be the only programs that work with the extra memory.

Edit: Found Feb 24, 1987 PC Magazine review of it which indicates it did not support either Expanded or Extended Memory even after more than 2 years on the market.

I believe it does not use EMS. It was released about the same time as the EMS was first announced. It may support the earlier Tall Tree standard or its own memory design. The disk cache and print spooler included with ITT's own DOS seem to be the only programs that work with the extra memory.

Edit: Found Feb 24, 1987 PC Magazine review of it which indicates it did not support either Expanded or Extended Memory even after more than 2 years on the market.

Hmmm... I have the original disks for ITT DOS 2.11 and the ITT Advanced Basic 2.0. Not sure how I would set the disk cache with ITT DOS, but from what you are saying it sounds like the extra memory on that card could only be used for specific purposes and not general purpose. Tell me if I am hearing you right. Thank you.

I believe it does not use EMS. It was released about the same time as the EMS was first announced. It may support the earlier Tall Tree standard or its own memory design. The disk cache and print spooler included with ITT's own DOS seem to be the only programs that work with the extra memory.

Edit: Found Feb 24, 1987 PC Magazine review of it which indicates it did not support either Expanded or Extended Memory even after more than 2 years on the market.

Man you were absolutely correct. After reading the following article it seems something called FXP from ITT would setup a hard disk cache and/or disk spooler that utilized that memory board if I am reading it right. About four paragraphs down in the article. I have ITT DOS 2.11, but am wondering if FXP was a separate disk that came with the system as I do not see anything on the 2.11 disk that relates to these features. I do see a hdsetup.com. Either way, I can't use it so 640K for me on this sytem. I'll just remove the expansion card and put it into climate controlled storage for now. Thanks for this info. It takes the mystery out of it at least.

Update: Actually I misread it. ITT DOS 2.11 has nothing that will take advantage of that memory expansion board. Only the additional ITT FXP utility will. Further down the article it explains the expansion board.

"Memory can be expanded beyond 640K with a proprietary expansion board from ITT. The board is available with 512K onboard and room for an additional 512K. The board can be used with FXP for cache and print buffering, with VDISK as a RAM disk, or via a software switch, as expansion memory for programs that take advantage of the Protected Virtual Address mode of the 80286."

It's not an AT keep in mind, but an XT with an 80286 retrofitted. It has 8 bit expansion slots. Anyome that's familiar with the machine knows this of course.

Which probably explains a lot as to why this memory expansion card can only do a couple of proprietary tricks. I did notice the few articles out there about the XP model refer to it as an XT/286 hybrid of sorts. This intrigued me even more of course as I only owned the XT model back in the mid 80s as a teenager.

From this article it looks like FXP was an upgrade memory software utility from ITT. It also came with new systems. Now I just need to find this FXP software utility so I can actually use this card for once. I don't think this will be an easy find. If anyone comes across ITT's FXP software I would deeply appreciate it if you could let me know. I'll keep hunting.

One of the articles quoted says that VDisk will work. If ITT's VDisk was the same as IBM's, then the memory expansion card would work with software using INT15 to access memory above 1 MB. So track down a copy of VDISK and see if you can get a RAMDISK that way. If that works, then other extended memory utilities that rely on INT15 should also work. INT15 is an unfriendly and slow interface with limited functionality so most programs defaulted to using XMS or tricks to directly access memory which requires adhering to the IBM AT standard. Check for option switches.